Electric motor



(No Model.)

' P. E. DAVIS 8: J. SCOTT, Jr.

ELECTRIC MOTOR. No. 425,991. Patented Apr. 22, 1890.

i Q s is? m 6 g 5 s si i? IIIVENTORS UNITED STATES FRANK E. DAVIS, OF BOSTON, AND JOHN SCOTT, JR., OF PLYMOUTH PATENT OFFICE.

MASSACHUSETTS.

ELECTRIC MOTOR.

SPECIFICATION forming part of Letters Patent No. 425,991, dated April 22, 1890.

Application filed November 19, 1889. Serial No. 330,879. (No model.)

To aZZ whom it may concern:

Be it known that we, FRANK E. DAVIS and JOHN Soo'rr, J12, citizens of the United States, residing, respectively, at Boston, in the county of Suffolk and Commonwealth of Massachu setts, and at Plymouth, in the county of Plymouth, in said Commonwealth, have invented certain new and useful Improvements in Electric Motors, of which the following description, in connection with the accompanying drawings, is a specification.

The object of our invention is to secure equality of speed between several motors and to provide means for stopping such motors simultaneously.

The invention consists in the arrangement and combination of devices, as hereinafter described and claimed.

In the drawings, Figure 1 is a side elevation of a machine embodying our improvements. Fig. 2 is a diagram of the electrical connections. Fig. 3 .is an enlarged detail View of the switch indicated in Fig. 2, and Fig. 4 is a diagram of certain electrical c011- nections to be referred to.

I Our improvements are applicable to any machine or plurality of machines wherein several motors are employed which it is desired should have the same speed; but for convenience we have herein set them forth as embodied in the winding or covering machine which forms the subject-matter of our applications, Serial No. 316,810, filed July 8, 1889, and Serial No. 323,804, filed September 13, 1889.

The single winder represented in Fi 1 consists, briefly, of the two covering-or winding heads B B and the winding or feed drum E, supported on a suitable frame A. The two winding-heads are alike, and a description of one will sufiice for both. Upon the frame is secured an electric motor D, having the usual armature B, field-coils B and fieldanagnet cores B and generally of usual construction. Secured to the end of the shaft 1) is the flier C, which may be of the same construction as those shown in our said application, Serial No. 316,810, being adapted to support a spool b of the covering material upon a hollow spindle b within the detachable yoke b. Upon the flier and normally held from contact therewith by the thread in its passage through the eyes I) and D is insulatingly secured a spring contact-point p, which is connected through connection 0 insulated ring 0 and conductor 0 with a generator K and magnet L, connections being also made from said magnet to the flier or its shaft through the conductor 0 and its contact-point resting'on the shaft, as indicated in Figs. 1 and 4. It will be seen that by this arrangement, which is the same as that shown in our said applications and forms no part of our present invention, but is presented as a convenient means for bringing our improvements into operation, the keeper of the magnet L will be attracted upon the breaking or failure of the coveringthread, for a purpose presently to be de scribed.

The current is conducted from the dynamo or other generator to the motors by the wires h h, in which a switch or cut-out G is inter posed for use when it is desired to cut out the machine entirely. From the switch G the currentis carried through the field-coils 13', through the usual resistances M, by which the motors may be adjusted to the same speed by the circuitJr h. As shown,the field-magnets of the two motors are arranged in multiple are; but, if desired, they may be in series, in which case but one set of resistances M will be needed.

The current is carried to both armatures of the two motors by the circuit 7L2 7L3, which, as clearly appears, is separate from the fieldmagnet circuit. As here shown, the armatures of the two motors are in multiple are. They may, if desired, be in series.

In the circuit 7L2 7L3 are interposed certain devices for regulating and shutting down the motors, which will now be described. The wire h as shown, passes directly to the armature; but in the course of the wire 72,3 is interposed a contactplate R in the form of an arc of a circle, in contact with which rests one end of a switch-lever P, pivoted at p, the other end of said lever resting normally upon the continuation of said wire its, and the lever thus forming a bridge over the break in said wire. The lever is subject to the action of a spring 0, but is restrained from movement path of the end of the lever is a series of resistances 00 x 09 having their contact-blocks separated by a space less than the width of the contact-face of the lever. Another resistance w is provided, having its contactblocks separated from the contact-block of the last resistance 00 by a space greater than the width of the contact-face of the lever. When one end of the lever P is on the contact-block of resistance 0: the other end will rest upon a contact-block Q, formed on the wire h The operation of the above-described devices is as follows: The upper end of the switch-lever P when released is thrown by the spring 0' toward the left, bringing its end successively in contact with the contactblocks of the resistances w 03 03 its lower end remaining in contact with the are R. The effect of this movement is gradually to increase the resistance of the armature-circuit, and thereby reduce the speed of the motor. The further movement of the switch-lever P moves the upper end of the lever oif from the contact-blocks of resistance m and at the same time moves the lower end of thelever off from the are R, thus breaking the circuit. The final movement of lever P brings its upper end onto the contact-block of resistance as, and at the same time brings its lower end onto the contact-block Q and closes the armaturecircuit on the resistances w m 00 as. It will be clear from this description that the action of the switch-lever when released is to suecessively insert resistances in the armaturecircuit, break the circuit, and short-circuit the armatures on resistance. The resistance on which the armatures are short-eircuited,

may, if desired, be separate from the resistances so ac xiwhich are inserted in the circuit.

By arranging both the armatures in the same circuit their rotation at the same speed is secured. If one armature tends to run faster than the other, the first will become practically a generator to the second and supply it with current to accelerate its speed, at the same time the extra effort exhausting its tendency to run faster.

It will be observed that the field-coils are unchanged in the ordinary operation of the machine, the switch G being used only when the whole machine is to be put out of use.

Having thus described our invention, what we claim is- 1. A plurality of electric motors having all their armatures in the same circuit, in combination with a switch in said circuit, and means for operating the switch to successively insert resistances in the circuit, break the circuit, and short-circuit the armatures.

2. A plurality of electric motors having all their armatures in the same circuit, in combination with a switch in said circuit, auto I matic means for operating the switch to successively insert resistances in the circuit, break the circuit, and short-circuit the armatures, and automatic means for releasing the switch to permit it to be operated by said firstnamed means.

3. A plurality of electric motors having all their armatures in the same circuit, in combination with a switch in said circuit, a spring for operating the switch to successively insert resistances in the circuit, break the circuit, and short-circuit the armatures, a catch engaging the switch-lever, and an electro-magnet arranged to operate the catch to release the switch-lever.

FRANK E. DAVIS. JOHN SCOTT, JR. Witnesses:

JOHN HERBERT, J OSIAH II. QUINCY. 

